Research and testing laboratories routinely receive biopsy tissue samples for analysis. These are usually embedded in a paraffin matrix, which is then cut into extremely thin slices for viewing under a microscope. The embedding process involves immersing the samples in a small container of melted paraffin, which then is allowed to cool and congeal. Great care must be taken to assure that instruments used in handling these samples do not accumulate congealed paraffin, which has cooled at room temperature after the instrument was dipped in the molten material. This could easily result in entrapment of a piece of a sample, and a transfer of sample material from one piece to another. The validity of the analysis of the sample could thus be compromised.
Handling these samples is normally performed with a forceps (or tweezers). To assure that congealed paraffin does not accumulate on the grasping portion of these instruments, it has become standard practice to repeatedly either dip them in a bath at elevated temperature, or expose them to an open flame. The flame is frowned upon in laboratories as a safety risk, but the necessity to keep the congealed paraffin from forming on the instruments results in relaxing the precautions. Any system for periodically exposing the instruments to a heat source interferes with the embedding operation, and increases the cost accordingly.